Hi All, I'm new here, and have just acquired a 1980 CB 750 Custom. Please could the wealth of knowledge on this site let me know - do the valve gaps need adjusting or are they hydraulic? Thanks.
The valves are not hydraulic, but are adjusted with various thickness of shims. Bears checking the clearance on a new-to-you bike, but often are found in-spec and the adjustment doesn't change often.
The dohc valve clearance are know to very often be to tight leading to low compression and burning the valves....very common issue. The factory clearance spec is too tight and needs to be opened up to .005" minimum on all valves. Definitely check and adjust the valves even if you need to buy some new shims. Dont cheap out and not adjust them, very important to engine life on the engines.